Chapter 14 - Alcohols Flashcards
What’s the functional group of alcohols?
-OH
Are alcohols polar?
Yes, they have polar O-H bond because of difference in electronegativity of oxygen and hydrogen atoms
What is volatility?
Measure of how easy a liquid is converted into a gas
Why do alcohols have a lower volatility than alkanes?
Have a higher boiling point
Why are the boiling points of alcohols greater than the boiling points of alkanes?
Strong hydrogen bonds between the O-H (polar) groups.
This requires more energy than overcoming the weaker london forces in alkanes.
Why are alcohols soluble in water?
Form hydrogen bonds with water.
between polar OH groups
Do alcohols get more or less soluble in water as the carbon chain increases in size?
-Less soluble.
As influence of the -OH group becomes relatively smaller
What are the 3 ways alcohols are classed?
- Primary
- Secondary
- Tertiary
What are primary alcohols?
- Alcohol where the -OH group is attached to a carbon atom that is attached to one alkyl group (and 2 hydrogens).
- e.g. ethanol
What is a secondary alcohol?
- Alcohol where OH groups is attached to a carbon atom that is attracted to one hydrogen and 2 alkyl groups
- e.g. propan-2-ol
What is a tertiary alcohol?
Alcohol where OH group is attracted to a carbon atom that is attracted to no hydrogen atoms and 3 alkyl groups.
e.g. 2-methylpropan-2-ol
What is complete combustion?
Combustion in plentiful supply of oxygen
What are the products formed in complete combustion of an alcohol?
carbon dioxide + water
Give the equation for complete combustion of ethanol
C2H5OH(l) + 3O2(g) -> 2CO2(g) + 3H2O(l)
Does the quantity of heat released per mole increase or decrease in combustion for longer chain alcohols?
Increases